Method of and means for heating forgings



Sept. 12, 1933. SPATTA METHOD OF AND MEANS FOR 'HEATING FORGINGS Filed Jan; 13, 1930 2 Sheets-Sheet 1 G. SPATTA 1,926,354

METHOD OF AND MEANS FQR HEATING FORGINGS 2 Sheets-Sheet, 2

Sept. 12, 1933.

Filed Jan. 13, 1950 fd7m (96 n TLOGN/Q fieorgefi Bcbtw Patented Sept. 12, 1933 METHOD or ANDMEANS Foe HEATING renames George Spatta, Buchanan, Mich, assignor to Clark Equipment Company, Buchanan, Mich,

a corporation of Michigan Application January 13, 1930. Serial No, 420,596

' "10 Claims. (or. .2ss-s In my copending application, Serial No. 416,

537 filed December 26, 15329, I disclosed a method of forming banjo type rear axle housing. for automotive vehicles from a cylindrical blank of seamless steel tubing, in which method the tub ing is first slotted at its central portion, then the end portions are swaged to reduce their diameter and to lengthen them, and the blanks thus formed are then heated and the central portion expanded toiform the banjo housing.

The present invention relates particularly to an improved furnace for heating the central portion of the slotted blank prior to the ex panding operation, and while the machine dis-. closed is primarily intended for this purpose, the principles of the invention are obviously applicableto machines designed to heat blanks f0 other similar forging operations. H

In carrying out the method of'my above mentioned copending application, the shaping of the banjo section of the housing is performedin two steps, the f rst of which merely expands the central section, flattening it from a cylin drical section to a fiat section, and the second shaping and foldingthat fiat section toform the banjo housing. In carrying out this method, I find it advantageous to perform most of the forgingoperation with asingle heating of the metal, that is, the blanks are fed through a heating furnace and delivered .thereflbm to the forging machines which perform their functions sufficiently rapidly to enable both machines to operate on the blank before it has cooled to such an extent that it must be reheated. Although the operation of thezparticular forging machines in question isfairly rapid, it is neverthelessnecessary to arrange-these machines so that the time lost in transferring the heated blanks from the furnace to the first machine and from the first machine to the second machine can be reduced to a minimum.

In carrying out a preferred embodiment of my invention, I position the two machines with their operating fronts adjacent, and mount the heating furnace overone of the machines. The hot blanks delivered from this heating furnace are lowered by a rapidly operating gravity means conveyor, which drops the blank into a rack conveniently disposed between the two ,machines and-slightly above the dies of these machines. H

Two workmen operating the two machines,

grab opposite ends of the hot blank and place it in the first machine, which is then operated to perform its step off-the forging process. The blank is then raised from this machine, transferred under the rack of the conveyor to the other machine and placed in the die of that machine. to complete the forging process, and the blank removed from the latter machine and sent on its way to. the nextstep in the process of theformation of an axle housing.

In order to insure that the two forging presses involved in this step of the process of manufacture are utilized to an economic extent, I have Thelatter machine is then operated timed the heating of the blanks so that'there is a minimum delay between the'successive operations of the machine. 1

To this end I have arranged the conveyor in heating arrangement so that another hot blank will be delivered to the 11 91;; between the-machines immediately after. the; finished blank has been removed from the second machine, This compels the workmen to work at a'definite rate of speed, since if they lag behind thehot blanks will, arrive before they have completed their step in forging of the previous hot-blank,--and ifthey are sufficiently slow more than one .fglank will be piled into the rack of their-machine. I have found tha by-suitablearrangement of the speed of heating the blanks and theti-ming ofv their delivery to :the forging machine, thernen can perform the forging functionin the allotted time throughout the'entire day (without undue fatigue, and that, the forging machine and heats,

ing. furnace are therefore efficiently used "and the production of thearrangement-is efficiently accomplished. s p

The elevated furnace which'I have placed over one of, the forging; machine's comprises arectangular steel casing suitably lined with a ree fractory material and provided-with slots in its opposite sides through which the .end sections of the blank are'projected. A chain, conveyor is ,disposed on the outside of the furnace, this conveyor having two sections, one on each side of the furnace and in approximate alignment with the slot in thefurnace. v Theconveyor contains a plurality of-hooks or other suitable projections which pick up theblanks from aloading platformand elevatethem into the furnace and through it to its discharge end. ,The speed of travel of the conveyor, is timed so thatthe blanks will be. in thefurnace long enough tobeheated to the propel forging ,1 which cases temperature, and the hooks on the chain are spaced so that the rapidity at which the blanks are delivered to' the discharge end of the furnace is correct to allow the operators of the forging machine suflicient time to perform the forging operations on one blank before the next heated blank is delivered to them.

The heated blanks leave the conveyor at the discharge end of the furnace, and are picked up by an inclined runway which delivers them to a vertically disposed gravity iconveyorthat lowers them to the rack between the forging machines. This gravity conveyor may conveniently be a chain conveyor provided with hooks for engaging the blank, or any other suitable type of conveyor capable of lowering the blank to the receiving rack. V

The furnace conveyor is power driven in any preferred manner, such as by an electric motor, and the vertical conveyor depends upon the weight of the blank disposed on one of its sides for its operation in lowering the blank.

While I have arranged the units of my invention in a particular manner to fit the invention to a particular set of manufacturing conditions, I am not to be limited to the specific details, since I am aware that the embodiment of the invention may be modified greatly to meet other manufacturing requirements.

Now to acquaint those skilled in the art with the teachings of my invention, reference is made to the accompanying drawings in which a preferred embodiment of itis shown by way of example and in which:

Figure 1 is a side'elevational View, partly in section, showing the furnace, the furnace conveyor, the gravity conveyor, and the forging presses in outline; a 2

Figure 2 is an elevational; view taken along a longitudinal section through the furnace;

Figure 3 is a transverse section through the furnace taken along the line 33 of Figure 2; and r Figure-4 'is' a detailed view'of the furnace conveyor chain and link thereon. 1

Referring to the drawings now in more detail, it'will be seen that the arrangement includes forging presses 1 and 2, which are disposed with operatin'gfaces 3and 4, respectively, adjacent. to eachother. The details of forging presses 1 and 2 are covered in my copending applications Serial No. 425,426, filed February 3,1930, and Serial No. 426,545,- filed February *7, 1930, to reference is here made for those details. I 9 The forging press 2 .is'operated first to per form the initial step in the expanding of the slotted blank toform a banjo housing; and the press 3 subsequently operated to finish the shaping of the expanded portion of the blank into the shape it'occupies 'in the completed housing.

The furnaceindicated generally at 5, is conveniently situated above and to the back side of I the forging press '1, this arrangement being ad- ,65'

vantageous in that it saves floor space in the shop,'and also in that it permits locatingthe furnace above the heads of the working men, so that the heat escaping from that furnace can be carried out of the shop to render the working conditions in the shop more comfortable.

A loading platform 6 is disposed at the extreme end of the framework '1' on which the furnace is supported, this platform 6 being in clined so that theblanks 8 placed thereon will roll naturally'toward the conveyor chainof the furnace. This conveyor chain 9 picks the blanks off of the loading platform 6 and elevates them to the slot 10 which runs in a general horizontal direction through the furnace 5 to the discharge end 11 of that furnace. The heated blanks pushed out of the discharge end of the furnace by the conveyor 9 roll down an inclined guideway 12 onto the hook 13 of the gravity conveyor 14, the weight of the blank causing the gravity conveyor to operate to lower the hook 13 to its lowermost position 15, in which position the blank falls from the conveyor onto the receiving rack 16.

The workmen pick the hotblank off the receiving rack 16, lower it over the dies of the press 2, operate that press, remove the blank therefrom and transfer it horizontally under the rack 16 to the press 3 and insert it in the dies of the latter press. In order that the space under the rack 16 may be kept clear, that rack is hung from the supporting framework 17 of the furnace in any preferred manner, as by the horizontal strut members 18.

The furnace comprises a steel shell 20 which is of generally rectangular shape and provided with a rectangular projection 21.. This shell has an open top, and is lined with a suitable refractory material 22 which protects the shell 20 from theheat of the flames within the furnace. A cover 23 is formed in a similar manner, and lined with a similar refractory material 24. The cover is closed at the top and open at the bottom, and the refractory material 24 supported in it by flanges 25 which are riveted to the side Walls 23 of the cover. The framework upon which the furnace is supported comprises vertical studs '7, 17 and 2'7, and suitable horizontal members 28 and 29 which fit beneath the casing 20 to support the furnace thereon.

The furnace cover is supported on these vertical members by flanges 30 and 31 riveted to the side walls of the cover and to the vertical members 27 a and 17, respectively. The projection of the cover is supported by horizontal cross members 32 which are attached to the vertical stud 7 and its companion stud on the opposite side of the machine andpositioned beneath the end of this extension.

In this manner, the furnace and cover are supported one above the other in such a mamier that the slots between the adjacent edges of the members are free so that blanks may be rolled through it. The vertical studs 7, 1'7 and 27 are spaced sufficiently far apart ,so that the blank will travel endwise between them without striking againstthem.

Additional horizontal studs 33 and 34 extending from the front to the back side of the framework are provided to support a platform 35 upon which the driving mechanism for the conveyor 9 is located. -This mechanism preferably comprises an electric motor which is connected to the conveyor 9 through a reduction gear, and since the arrangement is old and well understood by those skilled in the art it has been omitted from the drawings to avoid an unnecessary complication of the drawings. The 'platform35 also serves as a foot rest for a workman who is lighting thefire in the furnace or adjusting the conveyor or furnace mechanism.

Conveyor 9 comprises a chain 37 which is threaded over sprocket wheels 38, 39, 40 and 41, these sprocket wheels being keyed to shafts 38', 39, 40 and 11' which are disposed transversely of the machine in suitable bearings, (not shown) and which'contain similar sprocket wheels located onthe opposite --0r back side "of the machine. i I

A plurality of recessed cleats 4=2 are attached to the link of-the chain, and serve to-pick up the blanks 8 and to propel them through the furnace. 1 s

Flanges i3 and 44 are attached to the casing 20 of the furnace and disposed in a horizontal position below the slots between that casing and the cover 23 of the furnace. The chain links 37 rub on the horizontal members of these fianges'i3 and 44, and the cleats 42 of the chain are thereby disposed in a vertical position to push thebl'anks horizontally through the slot in the furnace. The end cylinders of the blank rest upon the edge of the casing and the blank rolls as it is pushed by the cleats. This insures uniform heating of the midsection of the blank.

This slot, as will be seen in Figures 2 and 3,

is just wide enough to clear the end sections of V the blanks 8, sotnat' the escape of heat through the slot is minimized. This loss of heat is further reduced by an inwardly, moving'stream of air drawninto the furnace through the slot to provide air of combustion to the burner, 'as'will presently appear. The slot contains a curved section 45 located injuxtaposition to the sprocket wheel 38, through which section the direction of the travel of the blank ischanged from vertical to horizontal. 1 V w I At the discharge end of the machinawhen the blanks engage the inclined runway 12, they roll away from the cleats 42, so that as the chain is moved around the sprocket wheel '38, these cleats may fall to a"horizontal position, then to a vertical position which is essentially upside down from thatwhich they occupy when driving the blanks through thefurnace.

The furnace 5 may be heated by gas or oil, which is blown into the furnace through the pipe 46 under suitable pressure controlled by the valve 4''! conveniently located at the end of the, furnace underneath the projection 21.

By this arrangement, the central and slotted section of the blank can be heated to the proper V in the furnace are prevented from coming in direct contact with the end sections of the blank,

those end sections are maintained relatively cool so that the cleats 42 and links 37 of the conveyor chain 9 are not damaged by being in contact with red or white hot metal. Furthermore, the end sections are sufficiently cool that workmen who are protected with suitable leather or asbestos gripping pads can handle the blanks by grasping their end sections without the use of tongs. l The burned gases from the furnace are conducted out of the cover through a suitable flue 48 which is'provided with dampers, (not shown) to regulate the draft through it. Air of combustion enters the furnace with the fuel, through the ports 45, and through the transverse slots 10 along the sides of the furnace, and I have found that this arrangement economically heats the blanks to forging temperature. The heat employed is employed at a point well above the heads of the workmen" so that the temperature in which they must work is moderate and they can, therefore, maintain a more rapid pace without undue fatigue.

While I have chosen to show a particular embodiment of my invention, I have done soby way of example only, .as there are many modifications and adaptations which can be made by one skilled in the art without departing from the teachings of my invention.

'a generally rectangular portion having a'horizontal projection extending from one end, a cover" for said furnace registering therewith, means for supportin said cover over the furnace but spaced therefrom, the bottom edge of the cover and the top edge Ofthfi furnace together defining a path leading; from the bottom of the projection upward and horizontally through the furnace, a refractory lining for the furnace and cover, and a burner for heating the furnace. V

'2. In a forging furnace, a casing having a generally rectangular portion having a horizontal projection extending from oneend, a cover for said furnace registering therewith, means for supporting said cover over the furnaoe butspaced therefrom, the'bottom edge the cover and thetopedge of the furnace together defining a path leading from the projection into and-through the furnace, a refractory lining ing the furnace. I 3. 'l\/feans for heating the-midsections of axle housing blanks or the like comprising, a furnace elevated above theheight of an attendant and having a firebox: 1 embracing the central parts of the blanks only, -the furnace having slots in the opposite walls thereof and the ends of the axle housing blanks extending out of the for the furnace and cover, and means for heat tire movement of the blanks through the fur ing the blanks crosswise through said firebox in spaced relation to each other, meansfor feeding blanks to the conveyor, a delivery rack furnace through said slots throughout the en- 7 below the'furnace for holding the heated blanks in definite delivery position, and an automatically operated lowering device for quickly covering the heated blanks and placing them in the delivery rack when they emerge from the furnace.

4. Means-for heating the midsections of generally cylindrical blanks comprising the com bination of an elevated firebox embracing the midsections of the blanks, the ends of the blanks extending through thefirebox, a rack upon which cold blanks are stored, a travelling conveyor embracing the outside of the firebox and engaging the extended ends of the blanks for carrying the blanks from said rack up to and through said firebox, a trough leading from the firebox down which the heated blanks roll free of said conveyor, a receiving means, and an automatic lowering device for carrying the heated'blanks to said receiving means.

'5. A forging furnace for heating the central sections of blanks comprising the combination of a fireboxlocated above the floor level and adapted to embrace only the central portions of' jacent said rack for removing the blanks therefrom by engaging, the ends, of the same and a horizontal portion adjacent the .firebox for tangular firebox having slots in its'side walls defining a passageway through which project the ends of the blanks that are within the firebox, conveyormeans located entirely outside of said firebox in juxtaposition to said slots, a rack for holding blanks, to be heated in said firebox,

means on said conveyor means for carrying said blanks from said rack through said 'firebox,

burner means in the firebox for heating the midsections of the blanks, a, fiue receiving the gases. of combustion and drawing in air through said slots, means for removing the heated blanks from said conveyor, a secondrack, and an intermittently movable device for rapidly moving said heatedblanks from said removing means to said second rack.

7. In combination, a forging furnace for heating the central sections of blanks to the forging temperature and including a heating chamber located above the floor level and having means therein for heating the blanks, a travelling conveyor having a vertically, moving portion for receiving the blanks by engaging the ends of the same and having a horizontal portion embracing the heating chamber for moving the blanks therethrough, a receiving rack located near the floor level, and a gravity conveyor receiving the heated blanks from the heating chamber and lowering the same and depositing them on the receiving rack. r

tending out through the slots, and means on the outside of the furnace for engaging the outwardly extending ends of the blank and advancing said ends along the slots to move the blank through the furnace.

9. The method of heating the central portion of an axle housing to the forging temperature which comprises, placing the central portion of the housing into a furnace, advancing the central portion through the furnace while maintaining the ends of the housing outside of the furnace and, throughout the heating of the housing, maintaining a movement of air into thefurnace from the region of the outwardly extending ends of the housing.

10.'The method of heating the central portion of an axle housingto the forging temperature which comprises, placing the central portion of theihousing into a furnace, introducing fuel and some air of combustion into the furnace, advancing the central portion of the housing through the furnace while maintaining the ends of the housing outside of the furnace and, throughoutthe heating of the housing, maintaining a movement of additional air of combustion into the furnace from the region of the outwardly extending ends of the housing.

- GEORGE SPATTA. 

